Traffic and Network Status Monitoring

Many technologies provide the basis for systems to monitor traffic levels and determine the real-time performance of a road network. (See Vehicle Detection and Probe Vehicle Measurement) The systems aggregate the data and make them available to the TCC operators and for Automatic Incident Detection (AID) systems. (See Automatic Incident Detection (AID)) Typically the components required for a highly reliable, fault-tolerant and flexible system architecture at the TCC - for the purposes of information collection, storage and presentation - may be split into four categories:

• control room display infrastructure such as those displayed below (See User Interfaces)
• operator workstations providing graphical display and selectable CCTV camera video streams that are configurable for each resident stakeholder (such as the TCC operator, police and breakdown recovery vehicle despatcher)
• one or more multiple-monitor display walls (including CCTV camera video matrices)
• hardware infrastructure: backup servers (to host all major central TCC functions, including their operating systems and applications), report printers and power supplies
• applications software: including those for network monitoring, real-time databases (to store and manage the distribution of all data collected), local incident detection algorithms, data aggregation and fusion applications, performance monitoring and Graphical Information System serving each operator workstation (See Basic Info-structure)
• telecommunications communication infrastructure: such as routers, hubs and associated management systems, plus interfaces to other systems and devices including other TCCs, remote vehicle detection systems, CCTV cameras and – if budgets permit, off-site backup servers or a fully functional Disaster Recovery (DR) TCC (See Telecommunications)

The TCC will also be equipped with telephone (conventional circuit-switched or Voice over Internet Protocol) and a Private Mobile Radio (PMR) system.

The key to successful traffic operations is inter-agency cooperation and coordination – for example between the TCC and other stakeholders such as the emergency services, major vehicle fleet operators, ports, airports and rail stations. (See Interagency Working).The extent of inter-agency cooperation has a major impact on the TCC’s operations and the support systems required. Integration can be facilitated by co-locating stakeholders in the TCC – as happened during the London Olympic Games.

When a new TCC is being planned or an existing TCC is being upgraded – it is important that the TCC system architecture (including the collection of traffic data) is aligned with the requirements of core applications. This is– usually split between highway management and arterial route management. These are often the responsibilities of different agencies but in future more integrated solutions may become available. (See Regional networks)

The system architecture should be designed to enable more efficient TCC operations at lower cost. For example, as the complexity of the network monitoring infrastructure expands, the architecture should provide for greater use of automated system health monitoring. This ensures that the TCC and field equipment are performing their expected functions properly. (See What is ITS Architecture?)

The use of proprietary interfaces for vehicle detection and traffic monitoring systems can increase the cost of expansion and increase the dependency on a small number of technology vendors and system integrators. Requiring standards-compliant interfaces can help retain supplier independence for the road operator – providing the requirement generates a market response. (See ITS Standards)

Any changes to a system needed to accommodate technology innovations is likely to impact on maintenance and operator workflow - requiring training, a revision to documented procedures and potentially – opportunities for innovation. For example, the use of a Knowledge-based Expert System (KBEST) to provide recommendations to TCC operators on traffic plans, is an innovation that can improve the efficiency of staff having to monitor several routes simultaneously. (See Future Trends)

CCTV cameras can help monitor traffic conditions, detect incidents, validate them, monitor the emergency services and help manage incident clearance. In some applications, 80% of incidents are detected with CCTV cameras – although their performance is compromised at night on routes without artificial lighting. CCTV cameras can be subject to vandalism and their communication cables subject to theft, even if optical fibre cables are used. TCC operators may wish to transfer some of the upgrade and operating risks to third parties (see box on Design, Build, Operate and Maintain - below). The involvement of third parties in data collection and data analysis (on an availability payments basis) can replace the need for expensive investment in additional network monitoring infrastructure.

Pressure on TCCs is higher than ever before in the face of:

• rapid developments in technology innovation
• the increasing number of technology options
• public expectation that traffic and travel information is timely and accurate

Traditionally, vehicle detection and traffic monitoring systems lacked the capability to perform data error correction, data analysis, self-diagnostics and reporting. As the capability of these systems has improved, more data needs to be exchanged with the TCC – and health monitoring may be centralised at the TCC.

In practice, each function of a TCC relating to network monitoring can be upgraded separately. This can be facilitated by dividing the TCC into functional modules and developing upgrade requirements for each:

• basic systems comprising video walls and operator workstations may be upgraded selectively - to accommodate greater areas of CCTV coverage and an increased number of sophisticated vehicle detectors and traffic monitoring systems
• video data streams from legacy analogue CCTV camera networks may need to be digitised to make them suitable for Automatic Incident Detection (AID) (See Automatic Incident Detection)
• many parts of the hardware and communication infrastructure can be upgraded to improve fault tolerance in the event of a single device failure
• an Uninterruptable Power Supply (UPS) may be added to ensure prolonged system operation in case of short-term power outages